Thanks for the help with the spoiler tag, I edited it. The extra password is 亜乃山の女, women of Anoyama. It unlocks the secret website with the full contents.
You get to see more speculation about the pheromones by the netori guy. He went back to the town after realizing he was hooked on sex with Anoyama women and met Touko again whos gone full slut. He also realized the Anoyama men must have special blood too and thats why Touko is hooked on the perv kid too. In the final page he says hes developed a desire to taste other Anoyama women and that most young ones are out in the city (reference to Misao and Tsubasa) so itd be a pain but he still wants to. If he does it hell update the site again. So please wait for the sequel lol.
I think that youre right about the game not having a big climax like the best venus games and fully developed mystery part. Whats there is good as always but this really feels like the first part of something much bigger. The order makes sense to me because his relationship with Touko was a bit superficial, mutual crush on a hot milf because they happened to meet at the right time. He was really hurt but the real chemistry all along was with Misao. If the sequel lives up to this itll be great.